#include<bits/stdc++.h>
#define int long long 

using namespace std;

signed main() {
	string s;
	cin >> s;
	int i = s.size() - 1;
	
	if(s[i] == 'n'  && s[i - 1] == 'a' && s[i - 2] == 's') {
		cout << "Yes" << endl;
	} else {
		cout << "No" << endl;
	}
	return 0;
}

